This invention relates to a method and apparatus for pulling boiler tubes from tube sheets and more particularly to the apparatus for breaking the seal between a boiler tube and a tube sheet.
Prior art believed to be relevant to the present invention includes: U.S. Pat. No. 2,507,201 issued to Evans on May 9, 1950; U.S. Pat. No. 2,744,429 issued to Seely on May 8, 1956; and, U.S. Pat. No. 3,245,247 issued to Valente on Apr. 12, 1966.
The Evans patent discloses the various problems involved in removing tubes from tube sheets and provides a one-piece cutter or plow-type tool for slitting the tubes from the outside of the tube sheet to thereby break the bond between the tube and the tube sheet.
The Seely patent teaches a particular type of tube crimper used in reducing the cross-section of a capillary tube to provide a precise flow resistance.
The Valente patent teaches a complicated device for pointing the end of tubing so that the tubing may be inserted into a drawing die.
Another method often used for removing tubing from tube sheets is by use of a cutting torch. This is particularly common in the case of large boilers using heavy walled tubing on the order of three inches in diameter. Errors in use of the cutting torch can, of course, damage the tube sheet requiring expensive refinishing and repair work. With such heavy walled tubing, the use of a cutter tool as taught by Evans is not practical.
Thus it is seen that there is a need for a simple method of removing tubing, especially heavy-walled tubing from tube sheets without damaging the tube sheet bonding surfaces.